如图甲所示,质量为m=1kg的物体置于倾角为θ=37°固定斜面底端,(斜面足够长

题型:计算题

问题:

如图甲所示,质量为m=1kg的物体置于倾角为θ=37°固定斜面底端,(斜面足够长),对物体施以平行于斜面向上的拉力F,t1=1s时撤去拉力,物体运动的部分v-t图像如图乙,试求

(1)物体与斜面间的滑动摩擦因数;

(2)拉力F大小;

(3)物体离开斜面时的速度大小。

考点:牛顿第二定律
题型:计算题

由于不可抗力解除合同的,发包人除应向承包人支付合同解除之日前已完成工程但尚未支付的合同价款,还应支付的金额包括()。

A.承包人撤离现场所需的合理费用,包括员工遣送费和临时工程拆除、施工设备运离现场的费用

B.发包人为合同工程合理订购且已交付的材料和工程设备货款

C.发包人为完成合同工程而预期开支的任何合理费用,且该项费用未包括在本款其他各项支付之内

D.已实施或部分实施的措施项目应付价款

E.合同中约定应由发包人承担的费用

题型:计算题

阅读理解。

     Sorry to say, our brains naturally start slowing down at the Cruelty young age of 30. It used to be

thought that this couldn't be helped, but new studies show that people of any age can train their brains

to work faster. "Your brain is a learning machine," says University of California scientist Dr. Michael

Merzenich. Given the right tools, we can train our brains to act like they did when we were younger.

All that's required is the practice designed just for the purpose: a few exercises for the mind.

     Merzenich has developed a computer-based training method to speed up the process(过程) in which

the brain deals with information (positscience.com). Since much of the data we receive comes through

     Over the course of training, the program starts asking you to distinguish (辨别) sounds (between "dog"

and "bog", for example) at an increasingly faster speed. It's a bit like tennis instructor, says Merzenich,

hitting balls at you ~faster and faster to keep you challenged (受到挑战). You may start out slow, but before

long you're pretty quick.

     The biggest finding in brain research in the last ten years is that the brain at any age is highly plastic. If

you ask your brain to learn, it will learn. And it may even speed up while in the process.

     To keep your brain young and plastic you can do one of a million new activities that challenge and excite

you: playing table tennis or bridge, doing crossword puzzles, learning a language.... "When it comes to

preventing ageing, you really do 'use it or lose it'," says Barbara Sahakian, professor at Cambridge University.

1. Dr. Merzenich's training method mainly depends on ______.

A. speech training

B. computer languages

C. the activities one joins in

D. the information being dealt with

2. By saying "the brain at any age is highly plastic", the writer probably means the brain can be_____.

A. used

B. mastered

C. developed

D. researched

3. What can we learn from the text?

A. Practice makes a quick mind.

B. Brain research started ten yeas ago.

C. Dr. Merzenich is a scientist in computer.

D. People believed nothing could stop the brain slowing down.

4. Which of the following agrees with the writer's idea?

A. The training methods work better for the old.

B. People should use the brain to stop it from ageing.

C. The training of the brain should start at an early age.

D. It's necessary to take part in as many activities as possible.

题型:计算题

盲探气管插管时,如出现导管探插受阻,管口呼吸音中断,并且可见颈侧近喉结处隆起包块,此时可能发生的情况是()

A.导管滑入一侧梨状窝

B.导管误入咽后间隙

C.导管误入食管

D.导管打折

E.导管进入气管

题型:计算题

在解决什么条件下电子签名具有效力的问题上,参照联合国贸易委员会()的规定。

A.电子商务立法

B.电子商务法

C.电子签名立法

D.电子商务示范法

题型:计算题

读图,回答问题。

为配合国家“送交通进山区”政策,某工程队在山区地形图中设计了施工的公路。

A处陡崖的高度差可能为()

A.100m

B.150m

C.300m

D.450m

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